:o :) I have this really good, self-propelled lawnmower. The problem is that I cannot pull the string to start it. My question is whether it is possible to convert the starting system to a button or key start. This would make my life immeasurably easier. Thanks for your help!

Maybe, but there is not enough info. The conversion might cost $200 or more.

Two methods are usually done:
1. 12 V battery - not recommended in this case
2. 120 VAC starting

The flywheel has to be changed, a starter + required electrical components are required and more importantly:

1. The flywheel with teeth must be available.
2. There must me mounting holes on the engine for the starter

Thanks for the info. I guess what I thought would be fairly simple is a lot more complicated than I thought! Oh, well! Now I guess I need a new mower!

It's not that bad of a conversion. Having a model # of the engine would help.
Electric start is a high cost option.

See:

Adding an Electric Starter

Electric Starter Kits

Kiss, is correct, it could be done possibly, but very costly.